diff --git a/.github/AGENTS.md b/.github/AGENTS.md
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+# GitHub Automation Rules
+
+## Standard
+
+- `GH-001` GitHub automation MUST be stored under `.github/`.
+- `GH-002` Workflow definitions MUST be stored under `.github/workflows/`.
+- `GH-003` Repository-local composite actions MUST be stored under `.github/actions/`.
+- `GH-004` Automation SHOULD use simple, explicit structures.
+- `GH-005` Names MUST be semantic and consistent.
+
+## Preferences
+
+- `GH-P001` Repository-specific preferences MAY extend rules defined in child directories.
diff --git a/.github/actions/AGENTS.md b/.github/actions/AGENTS.md
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+# Composite Action Rules
+
+## Standard
+
+- `ACT-001` Each composite action MUST be stored in its own directory under `.github/actions/`.
+- `ACT-002` Each composite action entrypoint MUST be named `action.yml`.
+- `ACT-003` Composite actions SHOULD represent reusable sequences of workflow steps.
+- `ACT-004` Each composite action SHOULD have one primary responsibility.
+- `ACT-005` Composite action directories MUST use simple semantic names.
+- `ACT-006` Composite actions SHOULD NOT be created solely to wrap a trivial single command.
+
+## Preferences
+
+- `ACT-P001` Composite actions SHOULD remain compatible with Linux runners where practical.
+- `ACT-P002` Platform-specific behavior SHOULD be avoided unless required by the action.
diff --git a/.github/workflows/AGENTS.md b/.github/workflows/AGENTS.md
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+# Workflow Rules
+
+## Standard
+
+- `WF-001` Workflows MUST be split by lifecycle concern.
+- `WF-002` Workflow filenames SHOULD use semantic names such as `ci.yml`, `deploy.yml`, and `release.yml`.
+- `WF-003` Reusable workflow filenames MUST use the pattern `reusable-*.yml`.
+- `WF-004` A `reusable-*.yml` workflow MUST use `workflow_call`.
+- `WF-005` Jobs MUST represent execution boundaries.
+- `WF-006` Independent jobs SHOULD run in parallel.
+- `WF-007` `needs:` MUST only represent actual job dependencies.
+- `WF-008` Matrices SHOULD only represent variations of the same job.
+- `WF-009` Job dependencies, conditions, and orchestration SHOULD remain explicit in workflow YAML.
+- `WF-010` Workflow and job identifiers MUST use simple semantic names.
+
+## Preferences
+
+- `WF-P001` Linux runners SHOULD be the default.
+- `WF-P002` A job that can execute correctly on Linux SHOULD run on Linux.
+- `WF-P003` macOS or Windows runners SHOULD only be used for platform-specific requirements or explicit compatibility testing.
+- `WF-P004` `lint-pr.yml` MUST NOT be modified.